A Location Based Service (LBS) is used to determine a location of a user through a location estimation technique and provides various information or services based on result of the determination. With the advent of smart phones and smart electronic devices, research into the location based service has been in active progress. Such smart phones and smart electronic devices comprises functions of a Global Positioning System (GPS), a terrestrial magnetic sensor, a camera, an Radio-frequency identification (RFID), or the like to provide various services and functionalities to the user.
The location based service researched in the related art primarily relates to an outdoor localization system such as a location estimation technique using the GPS and a mobile communication network, and a location estimation technique based on a pattern matching algorithm of a wireless LAN signal pattern, or the like.
However, the outdoor localization system is not suitable in an indoor environment as high accuracy is required to estimate the location. Due to influences such as signal interference by an indoor structure such as a wall, or the like, accurately estimating the location difficult in the indoor environment.
Korean Patent Publication No. 2014-0055109 (Apparatus and Method for Identifying Location of Mobile Node) discloses a technology that recognizes a location of a mobile node by using information on strength of a received signal transmitted from one or more reference nodes to a mobile node.
Korean Patent Publication No. 2014-0066570 (System and Method for Navigation) discloses a technology that attaches a barcode including identification information to a predetermined point indoors and recognizes and presents at which location a user is present in an indoor map by recognizing the barcode.
As described above, various technologies are developed for accurately estimating the location of the user positioned in indoor environment for various purposes such as the location based service, visitor location tracking, or the like.
However, since the location recognition technology can determine only a location at which the user is positioned in an indoor space and cannot verify at which degree and in which direction the user views at the location, there is a limit in that the location based service considering the location and a viewing direction of the user.